Burster cone for continuous miner boring head



y 1956 F. CARTLIDGE 2,754,100

BURSTER CONE FOR CONTINUOUS MINER BORING HEAD Filed Dec. 6, 1954 INVENTOR.

BY Frank Cartlidge flew W ATTORNEY United States Patent BURSTER CONE FOR CONTINUOUS MINER BORING HEAD Chicago, Ill., assignor to Goodman Company, Chicago, 11]., a corporation This invention relates generally to continuous mining machines, and more particularly to an improved center burster cone for the boring head of a McKinlay type mlner.

Improved machines of the general type referred to have been characterized by a boring head having a central pilot cutter generally in the form of a cone with a cutting spiral thereon. Such devices require a great deal of power, as measured by the reaction thrust against the boring head, and also by the large turning force required. A cutter of the aforesaid type is disclosed in Robbins application, Serial No. 440,466, filed June 30, 1954, for Mining Machine, owned by the assignee of the present invention.

According to this invention, achieved by an essentially cone shaped breaker which effectively bursts. or breaks the coal from the seam without the need for a cutting spiral on the tapered face of the cone. The pilot cutter accordingly has a cutter bit which cuts a generally cylindrical pilot bore, the action of the cutter bit being followed by a cone shaped breaker which wedges against the wall of the cylindrical bore to aiford clearance for the breaker. Very eifective breakage or bursting may be achieved by the use of pressure transmitting surfaces on the face of the cone, which act to maintain very finely ground coal against the seam. The dust-like coal acts in the nature of a medium to transmit pressure uniformly against the sides of a tapered bore in which the cone revolves. The pressure transmitting surfaces on the cone-shaped breaker may preferably have contours in cross section of segments of a circle with centers eccentric of the turning center of the breaker, and such surfaces act to wedge the fine material against the tapered bore, so that the longitudinal thrust against the breaker bursts the coal from the seam.

With the foregoing considerations in mind it is a principal object of this invention to provide an improved burster cone for the boring head of a continuous miner.

Other objects and important features of the invention will be apparent from a study of the specification follow ing taken with the drawing which together describe and illustrate a preferred embodiment of the invention, and what is now considered to be the best mode of practicing the principles thereof. Other embodiments of the invention may be suggested to those having the benefit of the teachings herein, and it is therefore intended that the scope of the invention not be limited by the precise embodiment herein shown, such other embodiments being intended to be reserved, especially as they fall within the scope of the subjoined claims.

In the drawing:

Fig. 1 is a reduced in scale side view of one of the boring arms of a boring type miner, said boring arm having a center burster cone according to the present invention mounted thereon;

Fig. 2 is a perspective view of the burster cone cutter central pilot cutting is 2,754,100 Patented July 10, 1956 breaker shown in Fig. 1, showing the action of the cone in bursting coal from a solid seam thereof; and

Fig. 3 is a cross sectional view taken along the plane indicated by the line 3-3 of Fig. 2, and looking in the direction of the arrows.

Referring now to Fig. 1 of the drawing, there is shown a boring arm 11 of a continuous mining machine of the type as disclosed in Robbins application Serial No. 440,- 466, filed June 30, 1954, for Mining Machine. Such a boring arm 11 is mounted to turn with a boring shaft 12 and is provided on the forward face thereof with supports 13 for cutter bits 14 mounted .at the end thereof whereby upon rotation of the boring arm 11 a plurality of concentric cuts are made in a solid seam of coal 16 or the like seen in Figs. 2 and 3.

A center burster cone referred to generally by the reference numeral 15 is mounted on the forward face of the boring arm 11 and on the turning center of the boring shaft 12. The function of the burster cone 15 is to provide a pilot bore for the boring arm 11 and additionally to remove coal from the solid seam 16 as with the cutter elements 14 mounted upon supports 13.

As seen in Fig. 2, the burster cone according to the present invention consists of an essentially circular base 17 which is held to the boring arm 11 by means of socket head screws 18. The base 17 has extending therefrom a cone shaped rotating support 19 which terminates in a generally cylindrical portion 21 remote from the base 17. The cylindrical portion 21 is slotted as at 22 at the forwardend thereof to receive a cutter bit 23 within the jaws of the slot 22 by means of the bolt and nut 24 shown.

The action of the cutter bit .23 is such as to make a cylindrical pilot bore, which becomes tapered by the action of the rotating tapered cone support 19.

The tapered cone 19 has a plurality of ribs 26 thereon, for purposes of illustration in this application four such ribs 26 being shown. Each of the ribs 26 has a leading edge 27 and a trailing edge 28, the two such edges being joined by a smooth surface having a contour in cross section, substantially in the form of a segment of a circle with the center thereof eccentric to the turning center of the boring arm 11.

The action of the cutter bit 23 is such as to create a large amount of fine dust which is carried behind the bit 23 along a bore 31 formed thereby, the dust moving between the ribs 26 and to be carried thereby as the support 19 and the ribs 26 rotate.

As seen in Fig. 3, the dust is swept ahead of the ribs 26, in such a fashion that it tends to be squeezed between the surface 29 of the ribs 26 and the side walls of a tapered bore 32 formed by the action of the ribs 26. As seen in Fig. 3 the ribs 26, in and of themselves do not supply any direct cutting action, as is the case of the cutter 23, but rather provide a means of wedging the fine coal dust in a direction from the leading edge 27 of the rib 26 to the trailing edge 28 thereof. The coal dust accordingly is required to occupy a smaller volume than it would normally occupy, and in so doing it operates to transmit what may be considered a pressure radial in direction to the turning axis of the cone 19, so as to burst the coal from the seam 16 as seen in Fig. 2.

The ribs 26 preferably have their surfaces 29 formed with some extremely wear resistant material such as tungsten carbide or Stellite.

Structure according to the present invention presents a number of advantages over burster cones of the type employing a spiral lead thread, such as disclosed in the aforementioned application, one of the advantages residing particularly in the fact that a lower reaction force is required by the burster cone, and also in the fact that 3 a smaller amount of power is required to turn the boring head 11.

While the invention has been described in terms of the preferred embodiment thereof its scope is intended to be limited only by the claims here appended.

I claim as my invention:

l. A burster cone for the boring head of a continuous miner for removing coal from a solid seam thereof, said burster cone being arranged to turn on the turning cen ter of said boring head and comprising a cone shaped rotating support, an extension from said cone shaped support having a cutting element mounted thereon for cutting a cylindrical pilot bore, a plurality of longitudinally extending ribs on said support arranged to wedge against the wall of said pilot bore and form a tapered bore, each of said ribs presenting in cross section a curved wedging surface with a leading edge of small diameter and a trailing edge of larger diameter so that the cuttings resulting from the rotation of said cutting element are wedged between said curved surface of said rib and the side wall of said tapered bore whereby pressure may be transmitted through the thereby confined cuttings to the said seam to fragment the coal therefrom.

2. A burster cone for the boring head of a continuous miner for removing coal from a solid seam thereof, said burster cone being arranged to turn on the turning center of said boring head and comprising a cone shaped rotating support, an extension from said cone shaped rotating support having a cutting element mounted thereon for cutting a cylindrical pilot bore, a plurality of longitudinally extending ribs on said cone shaped support, said cone shaped support being arranged in its turning movement to wedge against the wall of said pilot bore and form a tapered bore, each of said ribs presenting a wedging surface having a leading edge of a small diameter and a trailing edge of a larger diameter so that the cuttings resulting from the rotation of said cutting element are wedged between said surface of said rib and the side wall of said tapered bore whereby pressure may be transmitted through the thereby confined cuttings to the said seam to fragment the coal therefrom.

3. A burster cone for the boring head of a continuous miner for removing coal from a' solid seam thereof, said burster cone being arranged to turn on the turning center of said boring head and comprising a cone shaped rotating support, a plurality of longitudinally extending ribs on said support, said ribs forming a tapered bore in said seam, each of said ribs presenting a curved surface in cross section with its leading edge of small diameter and its trailing edge of larger diameter so that the cuttings resulting from the rotation of said burster cone are wedged between said curved surface of said rib and the tapered wall of said bore whereby pressure may be transmitted through the thereby confined cuttings to the said seam to fragment the coal therefrom.

4. A burster cone for the boring head of a continuous miner for removing coal from a solid seam thereof, said burster cone being arranged to turn on the turning center of said boring head and comprising a cone shaped rotating support, a plurality of longitudinally extending ribs on said support, said ribs forming a tapered bore in said seam, each of said ribs presenting a wedging surface having a leading edge of a small diameterand a trailing edge of a larger diameter so that the cuttings resulting from the rotation of said burster cone are wedged between said surface of said rib and the side Wall of said tapered bore whereby pressure may be transmitted through the thereby confined cuttings to the said seam to fragment the coal therefrom. 7

References Cited in the file of this patent UNITED STATES PATENTS 

